We obtained excellent diffraction data to 1.5 E resolution from crystals of trimethylamine dehydrogenase (TMADH). We collected data sets from native and substrate bound crystals. The spin-interacting state is formed in the crystal when substrate is added (based on microspectrophotometric measurements). Difference maps are pending. The processed data show significant intensities for systematically absent reflections; miss-indexing does not appear to be the source of the problem. The space group is under review.